Sharif Digital Repository

Silica nanoparticles is one of the most important mineral particles. In this study, Sodium silicate, Sulfuric acid and Sodium aluminate is used in order to synthesis of the modified Silica nanoparticles. The effects of temperature, reaction time and the molar ratio of regents were tested and optimized. Synthesized nanoparticles were characterized by use of XRD, FT-IR and SEM techniques. The results show that by controlling the reaction conditions, nanoparticles with an average size of 26.2 nm is obtained. The increase of temperature and reaction time alters the structure of the particles of amorphous state to a crystalline needles. The particle surface modification process was performed by... 

In this study, with respect to previous projects, we focused on size reduction of hollow and endohedral fullerenes research reactors. For this reason, we set up two reactors having 1/2 and 3 liters volumes and then such parameters as pressure, reactor temperature, arc duration time, arc time interval and the working electrical current through the electrodes circuit, in both reactors were optimized. The reactors, 3- and 1/2-liter reactors were of types of horizontal and vertical, respectively. In this project spatial angle between two electrodes were also found as effective variable on fullerenes yield in the 3-liters arc reactor for the first time. We found that upon correction of the... 

In this study, we synthesized ZSM-5 and doped ZSM-5 applying cations such as Zn(II) and Fe(II). Furthermore, we synthesized [Zn,Fe]-ZSM-5 using similar method for the first time. The final products were characterised by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. On the other hand, the hierarchical mesoporous Zn-ZSM-5 zeolite catalyst was prepared by alkali treatment by NaOH and Zn impregnation, and its application in the conversion of methanol to gasoline (MTG) process was studied. The modified zeolite samples after modification were also characterized by FT-IR and XRD methods. Zn impregnated mesoporous catalyst Zn-Alk-Z5 exhibited dramatic improvements in... 

In the present research, the conversion of methanol to hydrocarbons was studied over a new series of mesoporous low-silica HZSM-5 (Si/Al=11) catalysts impregnated with cations such as Fe, Zn, Mo and Cr. A systematic study on the effect of stepwise modification of the catalysts for the conversion of methanol to gasoline (MTG) was undertaken in a fixed-bed tubular reactor under ambient pressure at 375 °C, feeding with weight hourly space velocity (WHSV) of 2 h−1. The catalysts were prepared in the absence and presence of cationic promoted factors, in both alkaline and neutral aqueous solutions. The final catalysts characterized by using Fourier-transform infrared, X-ray diffraction, X-ray... 

In this research, four N2O2–azacrown macrocyclic ligands with naphthalene pendant arms (L1-L4) were synthesized using direct synthesis. The products were characterized applying 1H and 13C {1H} NMR spectroscopy, IR and Mass spectrometry. Interaction of these ligands with [60]fullerene and Cu(II) were monitored respectively by fluorescent as well as UV-vis spectroscopy and applying Benesi-Hildebrand equation. These intercations were compared with N2O2 macrocyclic ligands in previous experiments in terms of their calculated association constants (Ka). According to our results, the presence of naphthalene pendant arm groups led to increase the interaction with [60]fullerene compared to the... 

In our previous work in this laboratory, macrocycle containingO_2 N_2 and O_2 N_3- donor set with various ring size were synthesized. The intraction of macrocyles with [60]fullerene were determined. In this research, we synthesized 22-membered aza-crown macrocycle ligand containing O_4 N_2- donor set and characterized by NMRspectroscopy. The intraction of macrocycle with [60]fullerene were also investigated by UV-Visible spectroscopy. The formation constant was determined applying Benesi--Hildebrand equation. The result has been showed that O_4 N_2 macrocyle had better complexation with [60]fullerene in comparision of O_2 N_3 and O_2 N_2 donor sets. Then, the interaction of O_4 N_2 with... 

Fullerenes are molecular solid materials which are composed of 3D closed shell carbon-only structure. As soon as mass production of fullerenes was performed, the synthesis and characterization of endohedral fullerenes having at least one non-carbon element in the hollow fullerene cage, was started (in which about 30 atoms inserted in it so far). Furthermore, because of low efficiency and purity of these nano-particles, nowadays characterization of fullerenes is one of the most important research fields. In this project, we firstly optimized the fullerene production parameters in an arc discharge reactor to reach convenient efficiency. Then, the synthesis of endohedral fullerene by vaporizing... 

In this study, effect of chelate ligands containing carboxylic, phenolic, and amine functional groups on the synthesis of related-perovskite Ca2Fe2O5 versus perovskite CaFeO3 structures have been investigated. Herein, the application of chelating-agent method, e.g. EDTA, Citric Acid, NTA, malonic acid, maleic acid, catechol, acetylaceton, p-tert-butycatechol, aminophenolic derivative ligand, and 2-hydroxyiminodiacetic acid, in comparison to co-precipitation method was also undertaken. The crystalline structure of the obtained perovskites were compared with those of co-participation method in solid state. Experimentally, it was found that the related XRD bands for CaFeO3 were appeared in the... 

In our previous work, we have been undertake complexion of new amino phenolic ligand with Fe(III) and Co(II) in order to synthesis LSCF - and LSF - type perovskite inorganic membranes. In this study, the interactions between Co(II) and Fe(III) cations and the mentioned ligands were investigated their by cyclic voltammetry technique. In aqueous solution, it was found that chelate ring size has more prominent effect on the ligand-metal interaction than the related amino acid substitution. Accordingly, the amino phenol substituted... 

In this research, some inhibitors based on quaternary monoammonium salts and quaternary diammonium salts containing different anions were synthesized to prevent formation of methane gas hydrates, and they were characterized using 1H and 13C NMR spectra, IR spectroscopy, elemental analysis and mass spectrometry. Then, the synthesized compounds were used in an autoclave under 128 bar pressure under controlled isothermal conditions to determine retention time considering displacement amount of the gas hydrate temperature- pressure chart and also to determine subcooling of the samples using HW Hydrate software. According to the results T3, T4 and TBAHF compounds in their pure form, not only... 

In the present research, a series of bimacrocyclic tweezer anchored through azobenzene moiety were synthesized and characterized by applying IR spectroscopy, 1H and 13C{1H} NMR, fluorescence spectroscopy, UV-visible spectroscopy, mass spectrometry and elemental analysis and in some cases by X-ray crystallography. Firstly, UV-visible spectroscopy established that the irradiation of the tweezers with UV light promoted the trans to cis isomerization. On the other hand, thermal cis-trans isomerization behavior of the azobenzene moiety in tweezers was surveyed in which the cis isomers were formed of the heating at 50 oC for 5 minutes. Where the -OH group was replaced with 4-toluenesulfonyl... 

In the present study, the coordination chemistry of an amino acid azacrown macrocycle ligand bearing one carboxylic acid arm (MA1) was investigated by employing NMR spectroscopy, crystallography and computational chemistry. MA1 was synthetized by the reaction of chloroacetic acid with the parent azacrown macrocycle and its purity was confirmed with 13C and 1H NMR for the first time. A new MA1 homologue, MA3 was also successfully prepared and characterized with NMR, mass spectrometry, and elemental analysis. NMR studies showed that MA1 binds to cadmium via the carboxylate arm in solution. Crystallographic studies showed that MA1 formed a one-dimensional polymer with cadmium, wherein the... 

The purpose of this project is to synthesis of O2N3-azacrown ligands with 17 to 21 membered ring and investigation of their interaction with C60 according to increase ring size. These macrocyclic ligands can be used in C60 purification. In this project, change in macrocyclic cavity for finding the best macrocycle with appropriate cavity to C60 size has been considered. Firstly, five O2N3-azacrown ligands were synthesized and characterized by NMR spectroscopy and elemental analysis. Interaction of these ligands were considered by electronic spectroscopy applying Benesi-Hildebrand equation. According to the results, it was found that the best macrocycle for formation of stable complex with... 

The purpose of this project is the synthesis and characterization of a group of phenolic amino acidic derivatives that are studied in both solid phases as well as their solutions. For this, new phenol derivatives of serin and isoleucine amino acids were synthesized and characterized by 1H NMR , 13C NMR, IR spectroscopy as well as elemental analysis. These ligands were utilized to prepare LSF perovskite membrane. According to their XRD patterns, it was concluded that the powdered precursor prepared by serin derivative has shown better qualification and less intermediate phase in the synthesized perovskite membrane similar to the sample prepared by applying EDTA. Furthermore, in the previous... 

One of the most common methods of producing fullerenes is electric arc vaporization of graphite. Due to the low yield and purity of the nanoparticles in this method, the synthesis and isolation of the area research is important. In this work, the production was improved in a multi-channel arc reactor in which having horizontal graphite electrodes. The influence of various operational parameters such as pressure of inert gas, spark time, interval time between two sparks, voltage and current were completely optimized. Moreover, the prominent advantage of the new reactor was increasing the number of manufacturing units, at least from one to three, which the production of fullerene was... 

By considering previous works undertaken in our laboratory on the interaction between O2N2 azacrown and [60]fullerene using UV-vis spectroscopy. It was found that the significant interaction occurs in less than one hour. Extending this time in this research, the reaction between [60]fullerene with 15 to 19 membered N2O2-azacrown macrocyclic ligands was investigated during ten days. The new compounds L1, L2 were synthesized and characterized applying HPLC, ESI-Mass, TG, DSC, IR as well as elemental analysis. The interaction of new compounds with Cu(II) and Ni(II) and Co(II) using UV-vis spectroscopy showed that L2 gave the highest Kb value of cations/(L1, L2). Besides, it was found that the... 

In this research, a new group of N2O2–azacrown macrocyclic ligands with different macroring size from 15 to 18 was synthesized using one-pot facile and high yield reaction. The products were characterized applying FT-IR, 1H and 13C NMR spectroscopies as well as elemental analysis. The single crystal structure of 18-membered macrocyclic ligand was also determined by x-ray crystallography. The crystallographic data showed such strong inter-molecular hydrogen bonding which excluded their nitrogen-donor groups, and initial investigation with UV-Vis spectroscopy shows no intraction with [60]fullerene, despite of presence of these interacrtions in their parent macrocycles. The result of Job’s... 

A set of azacrown macrocyclic ligands bearing pyridine moiety (bp, 1p, 2p) were synthesized and characterized by single-crystal X-ray diffraction (SCXRD), elemental analysis, FT-IR, 1H and 13C NMR methods. The complexes of zinc tetraphenylporphyrin (ZnTPP) with the bp and 1p as the axial ligand were synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, IR, 1H and 13C NMR, fluorescence, UV-vis, cyclic voltammetry, together with TD DFT calculations. By employing this method for ZnTPPbenz and ZnTPPH complexes elucidated that the pyridine moiety was bonded through the fifth- coordination site on the zinc metal atom. In the following study, the coordination... 

By considering previous experiments undertaken in our laboratory on O2Nx (x=2,3) azacrown complexes with [60]fullerene, it was found that factors such as the macroring size, type and number of the donors groups in these macrocyclic ligands had significant effects on their selectivity towards [60]fullerene complexation. In this research, three N2O2N–azacrown macrocyclic ligand having uniform distribution of nitrogen atoms in macroring was synthesized using direct synthesis and high dilution method. The products were characterized applying 1H and 13C NMR spectroscopy as well as elemental analysis. Interaction of these ligands with [60]fullerene and Cu(II) were monitored by UV-vis spectroscopy... 

One of the considerable issues in fullereneresearch is low yield of endohedral fullerene production.In this project, synthesis and optimization of endohedral metallofullereneproduction was undertaken byarc reactor applying vertical graphite electrodes, using vaporizing composite lanthanum-oxide-graphite-dopped rod. Increasing the efficiency of endohedral fullerrene production in sootwas followed applyingcarbide formation in electrode which was studied by X-ray diffraction(XRD), thermogravimetric analysis(TGA) and infrared (IR) spectroscopy. In addition, as a simple and fast method, the liquid column chromatography was applied in separation and purification of fullerenes as well as endohedral...